Medical films are often used in surgical settings as a physical barrier to separate certain organs from adjacent tissues and medical devices following surgical intervention or blunt dissection to help minimize adhesion formation post-surgery. For example, SEPRAFILM® (a film composed of chemically modified sugars), a product of Genzyme Corporation of Cambridge, Mass., is used in abdominal or pelvic surgeries as an implantable treatment intended to reduce the incidence, extent, and severity of postoperative adhesion formation between different tissues and organs and implantable medical devices such as soft tissue support membranes and mesh, or combinations of non-absorbable materials and meshes.
One example of a medical film is described in U.S. Pat. No. 5,017,229. The film of the '229 patent is formed from a water insoluble, gel that includes the reaction product of hyaluronic acid (“HA”), a polyanionic polysaccharide, and an activating agent. The gel described in the '229 patent can be provided in the form of an adhesion prevention composition, such as a membrane or composition suitable for incorporation into a syringe. The gel is formed into a film by being cast into a sheet form, extruded, compressed, or allowed to dehydrate in a flat sheet. When modified with polysaccharide, the biodegradable film forms the above-described SEPRAFILM® adhesion-limiting or adhesion-barrier product made commercially available as a dehydrated bio-dissolvable single layer sheet.
Implantable medical films may be placed at a target site, for example, between two tissues, during surgery. In order to prevent or limit postoperative adhesion formation, the film should remain at the target site for a requisite period of time. For example, some sources have noted that barrier functionality is required between 3 days and 10 days post-surgery (see, Peritoneal Surgery by Gere. S. DiZerega, Alan H. DeCherney, Published by Springer, 2000, page 21). In order to achieve this barrier functionality, a biodegradable film should remain in place at the target site and it should be absorbed by the body for a sufficient period of time to provide barrier functionality post surgery when adhesions form.
However, conventional medical films are resorbed into the body too quickly to provide effective barrier functionality during the time in which postoperative adhesion formation typically occurs. For example, many cross-linked carboxymethylcellulose (“CMC”) based films may be absorbed in-vivo within 7 days.